Variable width die and method for extruding sheet products

Abstract

An apparatus and method for controlling in a variably controllable fashion the width of an extruder die opening whereby the width of material being extruded may be controllably varied.

That which is claimed is: 
     
       1. An extruder die for extruding extrudable materials comprising an elongated die body, at least one inlet into said die body, an extruder die opening and one or more side locking plates, said side blocking plates comprising a pivotally attached member wherein said pivotally attached member pivots around a pivot point within said side blocking plate and is variably extendible into said extruder die opening thereby variably reducing the width of said extruder die opening in a controllably variable fashion wherein the width of extruded materials is variably controlled. 
     
     
       2. The apparatus of claim 1 wherein the pivot member has a terminal curvature at the end closest to the extruder die lip whereby as the pivot member is extended into the extruder die opening a tangent on the pivot member at the point of the extruder die opening lip would be approximately perpendicular to the extruder die opening lip and generally parallel to the flow of extrudable material being extruded. 
     
     
       3. The apparatus of claim 1 wherein the pivot member has a length whereby when the pivot member fully withdrawn said pivot member extends beyond the extruder die lip opening. 
     
     
       4. The apparatus of claim 1 wherein the pivot member has a length whereby when the pivot member is fully withdrawn said pivot member is within the extruder die lip opening. 
     
     
       5. A method for varying the width of extrudable materials comprising attaching a blocking plate to an extruder die said blocking plate comprising a pivotally attached member wherein said pivotally attached member pivots around a pivot point within said blocking plate and is variably extendible into an extruder die opening thereby variably reducing the width of said extruder die opening in a controllably variable fashion and adjusting the variable extent of said pivotally attached member to variably control the width of extruded material. 
     
     
       6. The method of claim 5 which further comprises protecting a thermally sensitive extrudable material by cooling means. 
     
     
       7. The method of claim 5 which further comprises maintaining the extrudable material in an extrudable state by means comprising a heater. 
     
     
       8. The method of claim 7 which further comprises protecting a thermally sensitive extrudable material by cooling means. 
     
     
       9. The method of claim 5 wherein the extrudable material comprises a material selected from the group consisting of polymethyl acrylate, polyethyl acrylate, polymethyl methacrylate, polyethyl methacrylate, polystyrene, polyacrylonitrile, polyvinyl alcohol, polvinyl chloride, polyacrylamide, poly(2-hydroxyethyl) methacrylate, polydimethylsiloxane, polycarbonate, polyethylene, polypropylene, polybutylene, polyisobutylene, polymethylpentene, and mixtures, alloys, and copolymers thereof. 
     
     
       10. The method of claim 9 wherein the extrudable material is a material comprising a polycarbonate.